Trunk Wiring problems of the 2001 Mercedes Benz SL500

Vehicle was being stored in my garage . . I started the vehicle, it was sitting at an idle. . I noticed the battery light on the dash illuminate. Then I could smell burning. I noticed on the passenger side of the engine compartment smoke. I shut the car off. I opened the hood and noticed more smoke, burnt smell, the wiring harness was shorting and burning. The wrapping of the harness had a crisp feel to it. . As if deteriorating. I disconnected the battery to prevent any further damage or fire. I could hear the wiring shorting. My concern was the engine bay would erupt in flames in the garage, which then could spreading to my house.